Work is beginning on a new £700,000 visitor's centre at a fenland nature reserve.
The bittern's boom was first heard in May this year
The centre at the Royal Society for the Protection of Birds' Lakenheath Fen reserve on the Suffolk-Norfolk border is expected to be finished in December.
It will be the focal point for events and visiting groups and also provide offices and workshops for staff.
More than 2,000 people visit the reserve every year, but the RSPB hopes to boost those numbers to 60,000.
The fen was created from a 267-hectare carrot field bought in 1995 which was converted into reed beds.
In May, the booming sound of the male bittern was heard for the first time on the reserve, marking the success of a ten-year programme to bring the species to the fen.